Excitonic photovoltaic effect in a cyanine dye molecular assembly electronically coupled to n- and p-type semiconductors

Effects of physical orientation of dye molecules and molecular orbitals on performance of solid-state dye sensitized solar cells

Performance of Dye-sensitized devices depends on the photon absorption and carrier injection properties of the sensitizer (dye). The orientation of the dye molecule affects the photon absorption cross-section, injection efficiency and carrier transport. These effects are studied, using three variants of cyanine dyes in n-TiO₂/Dye/p-CuSCN heterojunction. The results show correlation of dye-molecule's orientation on the short-circuit-photocurrent (I_sc). The open-circuit-voltage (V_oc) is also subjective. The orientation of the dye molecule influence the photon-harvesting efficiency and obstruct the hole-conductor penetrating onto the working-electrode. Additionally, Cumulative effects of e-e, e-h, spin-coupling and HOMO/LUMO distribution are identified.

Introduction of various substitutions to the methine bridge of heptamethine cyanine dyes Via substituted dianil linkers

The unique optical properties of cyanine dyes have prompted their use in numerous applications. Heptamethine cyanines are commonly modified on the methine bridge after synthesis of a meso-chlorine containing cyanine. Herein, a series of heptamethine cyanines containing modified methine bridges were synthesized using substituted dianil linkers. Their optical properties including, molar absorptivity, fluorescence, and quantum yield were measured as well as their hydrophobic effects in polar buffer solution. It was shown that dyes containing cyclopentene in the methine bridge or a phenyl ring in the meso position display increased molar absorptivity while the increased flexibility of the dye containing a cycloheptene in the methine bridge prevented fluorescence.